I bought an 8x8 LED Matrix from eBay. I don't have the schematic so I used the diode testing functionality of my voltmeter. Once I saw how the connection were working, I tried to light one of them with the Arduino Uno.

I connected of the pin (+) of the matrix to a resistor (220 Ohm) and then to the 3.3V output of the Arduino, and the other pin (-) to the GND pin of the Arduino. It burned the LED.

I then tried something else: I connected another pin (+) to a 27K resistor and another pin (-) also to a 27K resistor and then to the GND. It nonetheless burned the second LED.

So before I destroy all the matrix, could somebody tell me what's i'm doing wrong?

So before I destroy all the matrix, could somebody tell me what's i'm doing wrong?

Basically no, because what you are doing sounds sort of OK.The bit that is not is that 3V3 from the arduino is limited to 50mA on many models of arduino.

So you are either not doing what you think you are doing, doing something else you are not telling us or have a very low current capable matrix.

I did get some RGB LEDs from ebay and I found that about three of the batch of 50 burnt out with only a few mA going through them. I also found that the red was rather dim on all but one of the LEDs. I think that some LEDs you get on ebay are actually from the reject bin.

I did get some RGB LEDs from ebay and I found that about three of the batch of 50 burnt out with only a few mA going through them. I also found that the red was rather dim on all but one of the LEDs. I think that some LEDs you get on ebay are actually from the reject bin.

Sure...but two 27K resistors? Nothing you could possibly do to a LED with 5V and a 27K resistor should kill it.

I'm going with your "not doing what you think you are doing" theory.

For starters: How does he know the LEDs are dead?

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

I know I burned the LEDs because when I tested after with the diode testing feature of the voltmeter, they didn't work anymore ; also with the 3.3V voltage they didn't work anymore.

Strangely enough, one of them worked, while the others burned out.

The LED in the LED matrix don't look light normal LED, they look like "flat LEDs". Is it normal or is it the sign of "low voltage matrix", what current should I put through the LED then and how can I know if the matrix is of this type?

I'm not finding anything with that part number.You should be able to safely use a 5V supply and a 1K resistor and be able to figure out the pinout for this part.(5-1.5)/1000 = 3.5mAThat shouldn't damage anything no matter what 2 pins you test to.